1. Field of the Invention
The invention relates to a security module for encrypting a telephone conversation between one or more first telecommunication terminals in a packet-oriented data network and one or more second telecommunication terminals in an analog and/or digital telephone network.
2. Description of the Related Art
Telephony in IP networks is known from the related art. Standards now exist in which the signaling for telephony in IP-networks is defined. The standards concerned here are the IETF Standard SIP and the ITU Standard H.323, which is also referred to as “Voice over IP” (VoIP) and is mainly employed in LAN or WLAN-based networks (LAN=Local Area Network, WLAN Wireless Local Area Network). With VoIP telephony security aspects have been mainly considered to date in relation to the authenticity and Integrity of control and signaling data. In future solutions, in addition to the pure signaling security, the security of the transferred voice data will also be considered. To secure voice data in IP networks for example the encrypted transport protocol SRTP (where SRTP=Secure Real Time Transport Protocol; see Baugher et al.; The Secure Real-time Transport Protocol; Work in Progress; search.ieff.org/internetdrafts/draft-ieff-avt-srtp-09.txt) comes into consideration.
With the current security solutions however only security of voice data in packet-oriented networks is guaranteed. Although security solutions also exist for telephony in public telephone networks, however there has not been an opportunity thus far for conducting encrypted telephone conversations from a packet-oriented network to a public telephone network.